Dried Beans and Peas - CNPP (DGAC)
To compare the effects of a chickpea-supplemented diet and those of a wheat-supplemented diet on human serum lipids and lipoproteins.
- Aged 30 to 70 years
- Not taking cholesterol-lowering medications
- Informed consent.
None mentioned.
Design
Randomized crossover design with twp intervention periods.
Intervention
Five-week interventions separated by eight-week washout period: Chickpea-supplemented diet and a wheat-supplemented diet:
- Chickpea diet: Daily consumption of 140g canned drained chickpeas, chickpea bread, chickpea shortbread biscuits (all provided to subjects; chickpeas = 300g net weight; 3.4mJ per day; 16% protein, 19% fat, 65% CHO; 27g fiber)
- Wheat diet: Wholemeal (wheat) bread, high-fiber (wheat) breakfast cereals (more than 2.5g fiber per 100g); shortbread biscuits (not provided to subjects).
Statistical Analysis
- Repeated-measures ANOVA by GLM to compare ingestion of nutrients during chickpea and wheat diets and to determine effects of diets on serum lipids and lipoproteins
- Univariate and multivariate analyses to assess associations between dietary intakes and lipid profiles
- All adjusted for order of interventions and blood sample collection.
Timing of Measurements
- Pre-intervention: Four-day weighed diet records to calculate usual EI
- Last week of each intervention, another four-day food record
- Fasting blood samples collected at the start and end of two dietary periods.
Dependent Variables
- Lipids (autoanalyzers)
- LDL-C (Friedwald equation).
Independent Variables
Dietary intake (four-day records; FoodWorks software).
Control Variables
Asked subjects to maintain physical activity and body weight, limit alcohol to two drinks per day, keep F/V and fat intake consistent with pre-intervention.
- Initial N: N=52 male and female
- Attrition (final N): N=47 (28 females, 19 male)
- Age: 53±9.8 years of age
- Anthropometrics: 79.3±16.3kg; 27.6±41kg/m2 (NS between start and end of each diet period, or end of the two interventions); NS differences for lipid profiles at start of each period
- Location: Launceston and Melbourne, Australia.
- NS differences in total EI between interventions; small but significantly lower protein intake and MUFA intake in chickpea intervention compared to wheat (P<0.001). CHO intake was significantly higher (P=0.02) on chickpea compared to wheat.
- Serum total-C was 3.9% lower (P=0.001) and LDL-C was 4.6% lower (P=0.002) at end of chickpea vs. wheat diet. Serum HDL-C and TAG NS difference between interventions
- Substantial effect of chickpea on whole serum total-C (P=0.001) and LDL-C (P=0.002) compared to wheat diet
- Dietary fiber showed strongest association, with a reduction in serum total-C of 0.24mmol per L (P=0.03) and in serum LDL-C of 0.21mmol per L (P=0.04) for each increase in SD in fiber intake. 55% of difference in serum total-C and LDL-C attributed to combined effect of fiber and PUFA in chickpea diet.
Chickpeas may have a role in reducing coronary heart disease risk by 13.5% through dietary intervention with fiber intake of approximately 30g per day.
Industry: |
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- Wheat and chickpea comparison: Chickpeas may have benefits beyond fiber (i.e., PUFA)
- Small sample size, conducted in two different centers (may be inherent differences in those two populations that may reduce effect).
Quality Criteria Checklist: Primary Research
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Relevance Questions | |||
1. | Would implementing the studied intervention or procedure (if found successful) result in improved outcomes for the patients/clients/population group? (Not Applicable for some epidemiological studies) | Yes | |
2. | Did the authors study an outcome (dependent variable) or topic that the patients/clients/population group would care about? | Yes | |
3. | Is the focus of the intervention or procedure (independent variable) or topic of study a common issue of concern to dieteticspractice? | Yes | |
4. | Is the intervention or procedure feasible? (NA for some epidemiological studies) | Yes | |
Validity Questions | |||
1. | Was the research question clearly stated? | Yes | |
1.1. | Was (were) the specific intervention(s) or procedure(s) [independent variable(s)] identified? | Yes | |
1.2. | Was (were) the outcome(s) [dependent variable(s)] clearly indicated? | Yes | |
1.3. | Were the target population and setting specified? | Yes | |
2. | Was the selection of study subjects/patients free from bias? | Yes | |
2.1. | Were inclusion/exclusion criteria specified (e.g., risk, point in disease progression, diagnostic or prognosis criteria), and with sufficient detail and without omitting criteria critical to the study? | Yes | |
2.2. | Were criteria applied equally to all study groups? | Yes | |
2.3. | Were health, demographics, and other characteristics of subjects described? | Yes | |
2.4. | Were the subjects/patients a representative sample of the relevant population? | Yes | |
3. | Were study groups comparable? | Yes | |
3.1. | Was the method of assigning subjects/patients to groups described and unbiased? (Method of randomization identified if RCT) | Yes | |
3.2. | Were distribution of disease status, prognostic factors, and other factors (e.g., demographics) similar across study groups at baseline? | Yes | |
3.3. | Were concurrent controls or comparisons used? (Concurrent preferred over historical control or comparison groups.) | Yes | |
3.4. | If cohort study or cross-sectional study, were groups comparable on important confounding factors and/or were preexisting differences accounted for by using appropriate adjustments in statistical analysis? | N/A | |
3.5. | If case control study, were potential confounding factors comparable for cases and controls? (If case series or trial with subjects serving as own control, this criterion is not applicable.) | N/A | |
3.6. | If diagnostic test, was there an independent blind comparison with an appropriate reference standard (e.g., "gold standard")? | N/A | |
4. | Was method of handling withdrawals described? | Yes | |
4.1. | Were follow-up methods described and the same for all groups? | Yes | |
4.2. | Was the number, characteristics of withdrawals (i.e., dropouts, lost to follow up, attrition rate) and/or response rate (cross-sectional studies) described for each group? (Follow up goal for a strong study is 80%.) | Yes | |
4.3. | Were all enrolled subjects/patients (in the original sample) accounted for? | Yes | |
4.4. | Were reasons for withdrawals similar across groups? | Yes | |
4.5. | If diagnostic test, was decision to perform reference test not dependent on results of test under study? | N/A | |
5. | Was blinding used to prevent introduction of bias? | No | |
5.1. | In intervention study, were subjects, clinicians/practitioners, and investigators blinded to treatment group, as appropriate? | No | |
5.2. | Were data collectors blinded for outcomes assessment? (If outcome is measured using an objective test, such as a lab value, this criterion is assumed to be met.) | Yes | |
5.3. | In cohort study or cross-sectional study, were measurements of outcomes and risk factors blinded? | N/A | |
5.4. | In case control study, was case definition explicit and case ascertainment not influenced by exposure status? | N/A | |
5.5. | In diagnostic study, were test results blinded to patient history and other test results? | N/A | |
6. | Were intervention/therapeutic regimens/exposure factor or procedure and any comparison(s) described in detail? Were interveningfactors described? | Yes | |
6.1. | In RCT or other intervention trial, were protocols described for all regimens studied? | Yes | |
6.2. | In observational study, were interventions, study settings, and clinicians/provider described? | N/A | |
6.3. | Was the intensity and duration of the intervention or exposure factor sufficient to produce a meaningful effect? | Yes | |
6.4. | Was the amount of exposure and, if relevant, subject/patient compliance measured? | Yes | |
6.5. | Were co-interventions (e.g., ancillary treatments, other therapies) described? | N/A | |
6.6. | Were extra or unplanned treatments described? | N/A | |
6.7. | Was the information for 6.4, 6.5, and 6.6 assessed the same way for all groups? | Yes | |
6.8. | In diagnostic study, were details of test administration and replication sufficient? | N/A | |
7. | Were outcomes clearly defined and the measurements valid and reliable? | Yes | |
7.1. | Were primary and secondary endpoints described and relevant to the question? | Yes | |
7.2. | Were nutrition measures appropriate to question and outcomes of concern? | Yes | |
7.3. | Was the period of follow-up long enough for important outcome(s) to occur? | Yes | |
7.4. | Were the observations and measurements based on standard, valid, and reliable data collection instruments/tests/procedures? | Yes | |
7.5. | Was the measurement of effect at an appropriate level of precision? | Yes | |
7.6. | Were other factors accounted for (measured) that could affect outcomes? | Yes | |
7.7. | Were the measurements conducted consistently across groups? | Yes | |
8. | Was the statistical analysis appropriate for the study design and type of outcome indicators? | Yes | |
8.1. | Were statistical analyses adequately described and the results reported appropriately? | Yes | |
8.2. | Were correct statistical tests used and assumptions of test not violated? | Yes | |
8.3. | Were statistics reported with levels of significance and/or confidence intervals? | Yes | |
8.4. | Was "intent to treat" analysis of outcomes done (and as appropriate, was there an analysis of outcomes for those maximally exposed or a dose-response analysis)? | N/A | |
8.5. | Were adequate adjustments made for effects of confounding factors that might have affected the outcomes (e.g., multivariate analyses)? | Yes | |
8.6. | Was clinical significance as well as statistical significance reported? | No | |
8.7. | If negative findings, was a power calculation reported to address type 2 error? | N/A | |
9. | Are conclusions supported by results with biases and limitations taken into consideration? | Yes | |
9.1. | Is there a discussion of findings? | Yes | |
9.2. | Are biases and study limitations identified and discussed? | Yes | |
10. | Is bias due to study's funding or sponsorship unlikely? | Yes | |
10.1. | Were sources of funding and investigators' affiliations described? | Yes | |
10.2. | Was the study free from apparent conflict of interest? | Yes | |